See on Plm 1:8. The imperfect tense, was fitting, or became fitting, points to the time of their entrance upon the christian life. Not necessarily presupposing that the duty remained unperformed. Lightfoot illustrates by ought, the past tense of owed, and says, "the past tense perhaps implies an essential a priori obligation."

In the Lord

Connect with is fitting, and compare well-pleasing in the Lord, Colossians 3:20.